Question

SELECT priceEach,
CASE WHEN SUM((priceEach/(priceEach) * 100) BETWEEN 19 AND 20 THEN 'yes' ELSE NULL hm
FROM orderdetails
WHERE hm = 'yes'
ORDER BY priceEach DESC;

这会有用吗？

我想不出如何找到对总体贡献20％的价格部分

Answer 1

这个答案完全基于我对这个问题的理解。不确定您是否正在寻找此结果。请试试这个：

SELECT priceEach,
       CASE WHEN SUM((priceEach/(priceEach) * 100) BETWEEN 19 AND 20 THEN 'yes' ELSE NULL END hm
FROM orderdetails
ORDER BY priceEach DESC
having Count(CASE WHEN SUM((priceEach/(priceEach) * 100) BETWEEN 19 AND 20 THEN 1 ELSE 0 end) = 1;

Answer 2

没有!!!你应该有 1. group by on priceEach喜欢这个群组（priceEach） 2. end像这样的案例

CASE WHEN SUM((priceEach/(priceEach) * 100) BETWEEN 19 AND 20 THEN 'yes' ELSE NULL end

你选择将是这样的

    SELECT priceEach,
    CASE WHEN SUM((priceEach/(priceEach) * 100) BETWEEN 19 AND 20 THEN 'yes' ELSE NULL end hm
    FROM orderdetails
    WHERE hm = 'yes'
group by priceEach
    ORDER BY priceEach DESC;

Answer 3

检查出来： - 我希望这就是你想要的。有点冗长，但值得努力。

RUN

Answer 4

在MySQL中，您可以使用变量执行此操作：

select od.*
from (select od.*, (@rn := @rn + 1) as rn
      from orderdetails od cross join (select @rn := 0) params
      where hm = 'yes'
      order by price desc
     ) od
where floor(rn / 0.2) = @rn;

将数据分成前20％的贡献

4 个答案: